Despite attempts to develop alternative and hybrid sources of propulsion, the motor vehicle industry remains dependent on the internal combustion engine for propelling the cars and trucks that have already been placed in service and those that are currently being produced. Although internal combustion engines and the associated components of vehicular drive systems have improved in efficiency, the input-to-output efficiency of internal combustion engines remains low.
The exothermic reaction of the internal combustion process creates gases at high temperature and pressure that can be translated into work, namely by driving the pistons of the engine. However, only a portion of the available energy is harvested and the remaining hot gases are vented to allow the piston to return to its previous position. Consequently, a significant percentage of energy in the form of waste heat is discharged to the atmosphere as hot exhaust gas and a further percentage must be removed from the engine through an air or liquid cooling system. Indeed, the exhaust and cooling systems have as their fundamental purpose the removal of waste heat that could not be exploited to produce work by the internal combustion engine.
Research has found that, out of the total power available in the consumed fuel, only approximately thirty percent of the gross available energy actually produces drive power as is shown in FIG. 1. Roughly thirty percent of the energy is simply exhausted by the exhaust system, and about the same percentage is removed by the cooling system. Furthermore, approximately another ten percent is employed to operate engine accessories such as the air conditioner, the fan, and the transmission. Even the roughly thirty percent of available energy that is directed to drive power is reduced by friction and other losses so that even less energy actually reaches the road surface.
Since there are millions of automobiles and trucks in use every day that together consume hundreds of millions of gallons of gasoline and diesel fuel annually, the amount of fuel that is effectively given off as waste heat is staggering. The lost energy contributes to mankind's dependence on fossil fuels and represents significant economic loss to individual consumers and society in general while having a deleterious effect on the environment. Consequently, it will be appreciated that an improvement in the efficiency of the internal combustion engine would represent significant benefits economically and environmentally while lessening the impact of vehicle usage on available petroleum resources.
Advantageously, a number of inventors have sought to provide methods and systems for harvesting the otherwise wasted heat from the internal combustion process. For example, in U.S. Pat. No. 4,224,797, Kelly discloses a steam turbine and power system that employs a closed Rankine cycle with a conical Tesla turbine. The system is said to be beneficial based on the efficiency of the Rankine cycle, quiet operation, few rotating parts, and reduced maintenance requirements in comparison to internal combustion engines. However, the power system in Kelly acts as the entire drive system for the automobile. Consequently, the system is difficult or impossible to apply to pre-existing vehicles. Furthermore, it is incompatible with internal combustion engines and, consequently, cannot practically be used to improve their efficiency.
In U.S. Pat. No. 5,000,003, Wicks teaches a combined cycle engine that seeks to provide improved fuel efficiency over liquid cooled internal combustion engines through the recovery of the engine's heat that would normally be ejected through the engine coolant radiator and the exhaust system. The energy harvesting aspect of the combined cycle engine operates under a Rankine cycle that requires a coolant pump, a super heater, a boiler, a feed heater, a turbine or other type of power producing vapor expander, an air cooled condenser, and a condensate feed pump. While Wicks expects markedly improved efficiency from such an arrangement, the system is highly complex and would require significant modification of existing systems or redesigned future systems to be able to be put into practice.
Even further, with U.S. Patent Application Publication No. 2007/0007771, Biddle et al. disclose a system for recovering waste heat from an internal combustion engine that again uses a closed Rankine cycle. Biddle et al. contemplate a system with specific relative temperatures as fluid advances from a first heat exchanger to an expansion unit. An electromechanical conversion unit is coupled to the expansion unit for converting mechanical energy to electrical energy. A cooling system is coupled to the expansion unit and the first heat exchanger for receiving and cooling fluid and supplying the fluid to the heat exchanger. Disadvantageously, however, operation of the system demands a multiphase process to heat the working fluid and a special turbine system involving a unique bearing and vane design. Furthermore, the turbine is coupled to the electromechanical conversion unit by a magnetic coupler such that the alternator is maintained separate and outside the working fluid of the recovery system.
In light of the foregoing, it will be appreciated that, despite the useful contributions of the inventors of the prior art, there remains a need for an auxiliary system for harvesting waste heat from the internal combustion process in automobiles that is efficient in structure and operation and readily adaptable to existing internal combustion engines thereby improving the input-to-output efficiency of the propulsion system and allowing a conservation of resources and concomitant economic and environmental benefits.
Unfortunately, internal combustion engines are not the only area of technology where available energy is incompletely harvested. For example, solar energy, although freely available, is almost entirely ignored. It simply heats the surfaces on which it falls with no intentional retrieval of its energy. While solar heat usefully imparts heating energy on buildings and other structures in colder conditions, it has a deleterious heating effect during summer months.
Accordingly, there has been a recognized and longfelt need for a system capable of retrieving useful energy from incident solar rays. Based on that need, solar heat systems and methods have been developed for application to rooftops and elsewhere for making use of the Sun's rays. For example, solar arrays have been developed that exploit the energy of the Sun to heat circulating water to provide some or all of a building's hot air and heated water. Furthermore, photovoltaic arrays have been developed for converting the Sun's energy to electrical energy. Over time, these systems have demonstrated improved efficiency and have been refined with the goal of providing the affordability required for widespread use.
Despite the improvements in systems and methods in the prior art, there remains a need for improved systems for harvesting solar energy. There remains a need for a system that is efficient and reliable in operation. Furthermore, there is a need for a system that can convert solar energy to useful work and power that is efficient in construction in a manner that permits its ready and cost effective application in a wide variety of environments.